An improved vehicle transmission shift control mechanism having an ignition interlock mechanism is described in copending U.S. Pat. application Ser. No. 137,759 filed Dec. 24, 1987, now U.S. Pat. No. 4,936,158 of common assignee herewith.
The transmission shift control mechanism described in that patent application includes a shift lever pivotal on a support base or frame between a "Park" position and other operative positions such as drive, reverse, neutral, etc. The shift lever is selectively retained in one of these positions by a detent mechanism which releasably couples the shift lever and a detent plate attached on the support base. The detent mechanism is manually released out of coupling relation between the detent plate and shift lever to free the shift lever for repositioning.
A locking mechanism is provided for preventing movement of the shift lever from the "Park" position when the vehicle ignition lock mechanism is actuated to the "Lock" position and for preventing such actuation of the vehicle ignition lock mechanism when the shift lever is in an operative position other than the "Park" position.
The locking mechanism includes a locking lever, such as a bellcrank, pivotally disposed relative to the detent plate. The locking lever is operably connected to the vehicle ignition lock mechanism for pivotal movement to a locking position relative to the detent mechanism to prevent release of the shift lever when the ignition lock mechanism is actuated to the "Lock" position with the shift lever means in the "Park" position.
The locking mechanism also includes a locking member such as an elongate locking pin carried on the shift lever mechanism for movement therewith along the locking lever to a cooperative position when the shift lever is placed in the "Park" position. In the cooperative position, the locking lever can pivot relative to the locking member to the locking position and, upon actuation of the ignition lock mechanism to the "Lock" position, blocks movement of the detent mechanism. The locking member is also movable along the locking lever to a non-cooperative position therewith when the shift lever is in positions other than the "Park" position. In the non-cooperative position, the locking member prevents pivoting of the locking lever to the locking position and thus prevents actuation of the vehicle ignition lock mechanism to the "Lock" position unless the shift lever means is in the "Park" position.
It is an object of the present invention to provide a service brake and shift lever interlock system for vehicle transmission shift control mechanisms including but not limited to the type described in the aforementioned copending patent application.
It is another object of the present invention to provide a service brake and shift lever interlock system having a control circuit to prevent shifting of the shift lever, unless the shift lever is in a non-drive position, such as the "Park" position, the ignition switch is in the "On" position (i.e., the "Start" or "Run" position) and the service brake system, such as the service brake pedal, is applied to brake the wheels of the vehicle.
It is another object of the present invention to provide such a service brake and shift lever interlock system which frees the shift lever for movement under other conditions.
It is still another object of the present invention to provide an interlock system having a bellcrank or other locking lever cooperable with the ignition switch mechanism to lock the shift lever in the non-drive position when the ignition switch mechanism is placed in the "Lock" position and also to lock the shift lever against movement when the ignition switch mechanism is in the "Start" or "Run" position, the electrical system is energized and the brake pedal is in the brake release position.